Electric switch



Oct. 8, I929. T. M. AVERY ELECTRIC SWITCH Filed July 22, 1921 2Sheets-Sheet 1 Z'we MA very,

T. M. 'AVERY ELECTRIC SWITCH Oct. 8, 1929.

Filed July 22,- 1921 2 Sheets-Sheet 2 PM ff. A any, %/W@ Patented Oct.a, 1929 UNITED STATES PATENT OFFICE 'rnv'n 1r. AVERY, or ens- 's mums,NEW ronx, assIGNoB 'ro UNIoN BAG ararnn' coBronarIoN, or NEW roux, N.Y., a conroRa'rroN or NEW Yomr n ELECTRIC SWITCH Application filed July28,

The present invention relates to im rovements injelectric switches orrelays an more particularly to those'of the kindused for controlling theoperation of a reversible electric 5 motor. I g The primary object ofthe invention is to provide'a novel and improved switch or relay of'thiskind which is capable of acting quickly and, if necessary, at' frequentintervals in response to -a suitable controlling device, to supplycurrent to a reversible electric motor to-cause running thereof ineither forward or reverse direction, the motor circuit-controllingcontacts being adjustable, whereby the gaps between them may be reducedto a minimum, and electro-magnetic devices operative in response to thecontrolling device servmg to so control the motor contacts that thedirection of 'running of the motor will be changed immediately or therunning of the motor initiated or interrupted promptly, as demanded bythe controllin device, thus enabling a very close regulatlongof themotor to be obtained.

To these and other ends, the invention con sists in certain improvementsand combinations and arrangements of parts, all as will be hereinaftermore fully described, the fea-. tures of novelty being pointed outparticularly in the claim at the end of the specification. I In the aompanying drawings Figure l i -epresents a front elevation of anelectric switch or relay constructed in accordance with the preferredembodiment of the invention;

through the switch or of Figurel; v 40 Figure 3 is a top lan view of theswitch or relay as shown m i rel; Figure 4 is a bottom view of theswitch shown in Figure 1; an Figure 5 represents diagrammatlcally acontrolling systememploying the or relaV 1 s an element thereof.

v Electric switches or relays embodying the present inventionareapplicable all installations where it is desira 1e or necesto sary tocontrol the operation of an electric .ing screw bein gener lly to 1921.Serial No. 480,740.

motor and especially a reversible electric motor. The invention isparticularly applicas ble to regulating or controlling systems, whereinthe electric motor is employed as a 'reglulating or compensating means,the switc or relay when used in such systems securing promptresponseofthe motor to the, device which controls it. In the present instance, theswitch or relay is shown generally as applied to a system forcontrolling the speed of a web of paper or other materialtravellingthrough a paper bag making machine or the like, for the purpose ofmaintainingcorrect registration between the travelling web and a deviceor mechanism in the machine which operates on the web, substantially asillustrated and described in my Patent No. 1,517,099, granted November25, 1924.

It is to be understood, however, that the in vention is not restrictedto this particular use and also that the invention is not restricted top the precise construction shown, as other uses 7 for the invention willsuggest themselves and equivalent constructions are contemplated, andthese will be included within the scope of the claim.

2 secure to its rear side and which serve to 30 support the switch orrelayaon a wall, the

frame of a machine or the like, it being preferable to so mount theswitch-or relay that t the base 1 occupies anupright position; A

removable cover '3 is preferably fitted to the a baselto normallyenclose and thus protect the Figure 2 represents a vertical section.relay on the line 2-2 and 7 and contains a socket 10 in which a contact11 ma be fitted adjustably, a clamp-,

I provided to secure the contact-in proper ad usted position. The base 1has a pair of terminals 13 and 14 secured 10o which latter extendpreferably through the base, as shown, and form bindingiposts for therespective motor connections. 'Additional screws 17 and 18 may beprovided to assist in securing the terminals 13 and 14 to the base. Eachterminal is provided with a contact holder which is formed with a socket20 to receive a contact 21 and a clamping screw 22 is provided to securethe contact in proper positionwithin its respective holder.

The ends of the blades or arms 4 and 5 opposite to the contact holdersare secured to a post or standard 23 which is secured rigidly to thebase by a suitable number of screws 24. Preferably, the rigidstifl'ening strip 6 of each blade terminates short of the post orstandard 23 and the relatively yielding or resilient strip 7 of eachblade serves to connect the same with the post or standard, under theclamping action of the screws 25.

Electro-magnets 26 and 27 are provided to actuate orcontroltherespective switch blades 4 and 5. Each of theseelectro-magnets has a core which is preferably in substantially the formof a horse-shoe, the poles of which are presented to the, armature 8 onthe respective switch blade, in order to secure a strong pull upon thearmature when thecorresponding electro-magnet is energized by a currentof relatively small strength. Preferably and as shown, the core of eachelectro-magnet comprises a pair of similar parallel pole-pieces 28 and29 which are connected at the rear of the base 1 by an iron plate 30,these parts forming a core of substantially horse-shoe form with thepoles thereof presented to the respective armature. It is alsopreferable to provide one of these pole-pieces with a winding, as isshown, in order to adapt the electro-magnet to operate under theinfluence of a current of small strength. When a single winding is used,the pole-piece which is without a winding will become a consequent poleto complete the magnetic circuit with the ara mature. An intermediatebinding post 31,

which is common to both electro-magnets,

and a pair of binding posts 32 and 33, which are individual to therespective electro-magnets, are preferably provided to enable thenecessary connections to be made. 1

Means is provided for adjusting the gaps between the contacts 11 of theswitch blades and the cooperating contacts 21 for the terminals 13 and14,.in order to secure prompt engagement of these contacts when their respective electro-magnets are energized. Breterably and as shown, a post34 is fixed by the screws 35' or otherwise tothe base 1 at a pointadjacent to the contact-carrying ends'of the switch blades and this posthas oppositely-extending arms 36' which overlie the switch blades 4and 5and carryset'screws 37 which are adjustable in the respective arms ofthe post and are arranged to bear against the averages outer sides ofthe respective switch blades. By this arrangement, the set screws 37will limit the outward swing of the switch blades, and hence willcontrol the air gap between the armature and the electro-magnet of therespective switch blade, and these set screws will also control the airgaps between the contacts 11 on the respective switch blades and thecorresponding relatively fixed contacts 21 on the base. The contactsordinarily will be adjusted so that this air gap is substantiallyconstant, usually about one-quarter of an inch, thus maintainingconstant the, distance throughwhich each switch arm must move,

in order to engage the respective pair of con-,

13 and 14, through the respective switch blades 4 or 5. Preferably andas shown, the

line terminal is connected to one side of a fuse-block38, the otherterminal of which is connected by a conductor 39 to the post or standard23, by a screw 40.

One example of a practical application of the switch or relay is showndiagrammatically in Figure 5. In this instance, it is employed, for thecontrol of an electric motor which functions to compensate forvariations in the speed of a travelling web and to thereby maintain,within relatively close limits, correct registration between the web anda de vice or rnechariism which operates thereon. 41 represents areversible direct current motor of the type using three terminals, theterininal 42 .being connected to the conductor 43 which is connected toone side of the line circuit which may supply current at the usualvoltage, the terminal 44 of the motor is connected by a conductor 45 tothe terminal 14 of the switch, the terminal 46 of the motor is connectedby a conductor 47 to the terminal 13 of the switch, and aconductor 48,which is connected to-the other sideof the line circuit, extends to thefuse-block 38. The electro-magnets which control the switch blades arepreferably connected in aseparate or local circuit which may be adaptedto carry a current of relatively low voltage. As indicated, B representsa battery having a switch S connected therein and one side of thisbattery is grounded on the frame of the machine on which the system isused, as indicated at G. The conductor 49 of this local circuit leads tothe common binding post .31 for the two electromagnets-26. and 27, thisbinding post being connected to one tcrminalof each electro-magnetwinding. The other terminals of the electro-magnets which areconnectedto the mounted on a shaft 54, so that they will be revolved in definitetimed relation to the speed of operation of the device or mechanismwhich is to be registered with the web, these contacts being connectedrespectively to col-' lector rings 55 and 56, and the conductors 50 and51 being connected to brushes 57 and 58 which constantly engage therespective collector rings, and a controlling contact 59 which iscarried by a sprocket 60, which is freely rotatable relatively to thecontacts 52 and 53 and is driven in accordance with the actual speed ofthe web, is caused to engage one or the other of the contacts 52 or 53,when variations in speed occur between the contacts 52 and 53 and thecontact 59. The contact 59 is grounded on the frame of the machine, asindicated at G, through the shaft 54.

The mode of operation of the system thus described is briefly as follows:-When the controlling contact 59 is in a neutral position between thecontacts 52 and 53, the local circuit of'the switch will be open and, inconsequence, the motor circuit through the conductors .45 and 47 will beopen, and hence the motor will be at rest.v Should-the speed of the webaccelerate relatively to the speed of operation of the device ormechanism which is timed with the shaft 54, the contact 59 will engagethe contact 52, thus completing the local circuit through theelectro-magnet 26, in consequence of which the switch blade 4 will beactuated to engage its contacts 11 and 21, and the motor circuit willthen be completed through the conductor 47. The motor will then run inone direction, andthrough the medium of the compensating mechanism whichis fully shown and described in my application above referred to, itwill retard the speed of advance of the web. Should the speed of the webbecome retarded relatively to the speed of operation of the device ormechanism which is timed with the shaft 54, the controlling contact 59will engage the contact 53 andithe local circuit will then be closedthrough the electro-magnet 27, in consequence of which the switch blade5 will be actuated to-engage its contacts 11 and 21, thus completing themotor circuit through the conductor 45. The motor will then run in anopposite direction, and through the medium of compensating mechanism asabove referred to, the speed at which the web is advanced through themachine will be accelerated. As soon as the necessary correction hasbeen made in the speed of the web, the controlling contact 59 willresume a neutral position between the contacts 52 and 53 and the motorcircuit will be broken through the conductors 45 and 47.

A It is to be understood that the switch members have a normal tendencyto disengage the contacts'when said members are not attracted by theirelectro-magnets. By mounting the switch in upright position so that theswitch members are arranged vertically or substantially so, the switchmembers may be so balanced that a very delicate force will be sufficientto attract them and thereby cause engagement of the contacts.

By arranging the electro-magnetS in close proximity to the pivotalpoints of the switch blades and the motor controlling contacts at thefree ends thereof and remote from their pivotal points, quick action issecured in the contact engaging and disengaging operations, and thisaction is assisted, to a great extent, by the regulating screws whichregulate the air gaps between the contacts within relatively closelimits, with the result that the motor or other device controlled by theswitch will respond instantly to the demands of the controlling device.The switch will therefore insure close and correct regulation when usedin a regulating system, and furthermore, itis adapted for use insituations where the switch is required to operate frequently or atcuit-controlling contact at its upper end, a

fixed circuit-controlling contact mounted at one side of said member tobe engaged by the contact thereon when said member moves in onedirection, an electro-magnet located at the same side of said switchmember at which said fixed contact is located and operative, whenenergized, to move said member immediately in a direction and to anextent suflicientto cause engagement of said contacts, and a stopmounted at the side of the switch member opposite to that side atwhichthe electro-magnet and fixed contact are located, the switch memberhaving a normal tendency to rest against said stop, one of said contactsbeing adjustable in a direction toward or from the other contact todetermine the gap between said contacts when the switch member restsagainst said stop and to space the switch member from theelectro-magnet' when said member is in attracted position, and said stopbeing adjustable to limit the retraction of the switch member and todetermine the gap between said contacts and also the gap between theswitch member and the electro-magnet when the switch member isin-released position.

In testimony whereof I hav e hereunto set

